This general statement, however, requires qualifica tion. The north-western border does experience cold such as is felt in no other district. In winter the Punjab is the coldest part of India, while Sind and the Baluchistan highlands to the west, though extremely hot in summer and during the day, may at night even in autumn experience many degrees of frost. Here, then, you would expect to find that the Indian type of civilization is somewhat modified.
If we consider the rainfall and the effects of heat and rainfall on vegetation, we see that the northern plain at its eastern entrance is drenched with rain and so near sea-level that the water cannot run off; thus it is wet and marshy and therefore jungle-covered. As one goes westwards the conditions change imperceptibly. There is less rain and the water has somewhat more chance of running off, till 1000 miles from the sea the supply of water is deficient. Continuing to the mouth of the Indus the land becomes drier and drier, and the last 400 miles is steppeland or even desert. The western slopes of the southern plateau and the southern slopes of the Himalayas, and the highlands north-east of the Bay of Bengal, are also drenched with rain in summer, and retain enough moisture to allow of the growth of forests, which become jungle in the lower and damper areas. The south-west monsoon which deluges the Western Ghats blows up the straight valleys of the Narbada and Tapti, and carries heavy rain farther inland here than elsewhere, while eastwards the air current meets that which has come more directly from the Bay of Bengal, and induces a heavy rainfall over the land from the heads of these two river valleys, even to the cOastlands south of the Ganges' mouths. Here the soil is a heavy black clay, so that a belt—part forest, part jungle, and in part now cultivated land ex6ends across the northern part of the peninsula from Gujarat to the Mahanadi delta. South of this belt, with the exception of the river valleys and the coastal plains, the land is drier and for the most part grass covered.
The same conditions extend over great distances, and the land is difficult to organize and keep organized. The reason is not only that it is too large to organize as a whole by people unaccustomed to organization— that would not be wonderful; Europe even now, though organized, is not organized under one government—but also that the natural divisions are too large ; there is no nursery like Egypt or Babylonia or the Wei Valley, where life is comparatively easy, where the unit is small so that men might learn methods of government and organization, and yet where there is need for fore thought.
Thus, while the heat and moisture combine to fix solar energy in a form suitable for human use, there is less stimulus to save this energy individually, less stimulus and ability to organize communities to save energy or to protect energy that had been saved. Indian civilization has always been less advanced than ex ternal civilizations in the genius for organization, and whether in peace or war immigrants have organized and dominated with greater or less success the peoples among whom they came.
And whence have these immigrants come ? To under stand the answer note the obvious fact that India is a Continental Peninsula. It is, on the one hand, far nearer the dry heart land of Central Asia, the home of the nomads, than is either Europe or China, and, on the other, though there is little temptation to natives of India to become seamen or force to make them so, the land is still open to approach from the ocean. From north-east overland, from north-west overland and from the sea, India has been entered by greater or less numbers of people.
From beyond the forested north-eastern border, by ones and twos through that forest and jungle, men have wandered and entered the jungle lands of India. These are no organizers ; they have formed no states. A forest, as we have seen, is at any time one of the great barriers to organized movement, and when those forests grow on the sides of deep steep-sided valleys, one behind the other, it is no wonder that the north-eastern approach has never been effectively used.
It is very different with the north-west. Here, as we have seen, it is dry; no forests bar the way, and India is here in touch with two virile civilizations. Across the comparatively narrow, if high, mountain ranges which fan out from the western end of the Himalayas lies the great plain with its steppeland peoples ; while by the northern and southern mountain edges of the Iran plateau, where streams descend from the hills, are ways to the lands with old civilizations—Persia and Babylonia and Assyria. Those peoples who from the mountains have looked out on the north-western plains of India will be tempted down, for there may at times be felt there a refreshing coolness like that to which they have been accustomed, and for which they have been prepared.